Stability control systems, such as vehicle chassis and suspension systems employ stiffness control elements including torsion bars, shock absorbers and other linkage and dampening mechanisms to affect ride stability, ride comfort, and roll performance of the vehicle. Ride control requirements for ride comfort, vehicle handling, vehicle stability and ground holding ability can vary significantly as driving surface conditions vary, and passive systems are limited in the range of varying conditions to which the system can respond. For example, conventional passive anti-roll torsion bars are designed with sufficient stiffness to resist vehicle roll when cornering, which may contribute to suspension harshness when the vehicle is not cornering and therefore represent a non-optimized stiffness control solution. Active or semi-active systems are available which respond to varying ride characteristics and stability control requirements, at additional expense and complexity. For example, active anti-roll bars may be configured with hydraulic actuators or electromagnetic motors which are costly, complex and require additional controls and packaging space in a vehicle.